An in use table manager in a computer system uses an in use table to track the use of files, or objects. The in use table is used to determine which objects may need recovery in the event of a system failure. Object addresses are hashed by the in use manager to identify a preferred slot in the table. The slots contain information identifying the object, and indicating the extent of use of the object. The in use manager assigns alternate slots, and dynamically changes the size of the in use table to reduce contention for slots. Several atomic operations on the table ensure integrity of the table, while permitting concurrent use. Portions of the table are bundled into single I/O operations to enhance system performance by minimizing I/O.